The present disclosure, for example, relates to wireless communication systems, and more particularly to smart grouping techniques for multi-user multiple-input/multiple-output stations.
Wireless communications systems are widely deployed to provide various types of communication content such as voice, video, packet data, messaging, broadcast, and so on. These systems may be multiple-access systems capable of supporting communication with multiple users by sharing the available system resources (e.g., time, frequency, and power). A wireless network, for example a wireless local area network (WLAN), may include an access point (AP) that may communicate with one or more stations (STAs) or mobile devices. The AP may be coupled to a network, such as the Internet, and may enable a mobile device to communicate via the network (or communicate with other devices coupled to the access point in a service set, e.g., a basic service set (BSS) or extended service set (ESS)). A wireless device may communicate with an AP bi-directionally. For example, in a WLAN, a STA may communicate with an associated AP via downlink (DL) and uplink (UL). From the perspective of the STA, the DL (or forward link) may refer to the communication link from the AP to the STA, and the UL (or reverse link) may refer to the communication link from the STA to the AP.
An AP communicates with more than one STA simultaneously in a multi-user multiple-input/multiple-output (MU-MIMO) transmission. The AP assigns a group of STAs to a MU-MIMO group and sends a MIMO transmission to the group of STAs of the MU-MIMO group that each have data ready for transmission. With opportunistic scheduling, the AP changes the STAs assigned to the MU-MIMO group during every sounding period based on, for example, availability of traffic, modulation and coding scheme (MCS) compatibility, etc. However, when a STA is grouped with other STAs in a MU-MIMO groups that are incompatible (e.g., where STAs in the group have high mutual channel correlation), the packet error rate (PER) for the MU-MIMO group may increase for the group due to inter-user interference.